Moderate exercise reduced women’s stroke risk

Moderate exercise significantly reduced the risk of stroke in women and seemed to offset much but not all of the increased stroke risk in postmenopausal women on hormone therapy, a large retrospective study found.

A self-reported history of moderate to strenuous physical activity in the prior three years was associated with a roughly 20 percent-30 percent lower risk for stroke in an analysis of data on 133,479 women in the California Teacher Study who had been followed every four to five years since 1995 by questionnaire.

They linked the data set with hospitalization data during 1996-2010 to identify 2,416 ischemic strokes and 710 hemorrhagic strokes in the cohort that were validated by a review of medical records.

The strongest reduction in stroke risk was seen in women who reported moderate physical activity such as brisk walking, recreational tennis, golf, volleyball, or cycling on level streets. Women who reported in 1995-1996 questionnaires that they had engaged in moderate activity in the prior three years were 12 percent-22 percent less likely to develop a stroke, depending on the amount of activity each week, compared with inactive women who reported less than half-hour per week of moderate activity.

“You don’t have to climb a mountain” to gain the stroke-reducing benefits of exercise, said in the International Stoke Conference. And the fact that people tend to over report how much they exercise when surveyed makes the findings “particularly robust.”

Indeed, reports of strenuous activity were not significantly associated with lower stroke risk. Strenuous activity included swimming laps, aerobics, running, calisthenics, jogging, basketball, racquetball, or cycling on hills. Risk levels ranged from an increase of three percent to a reduction 18 percent with strenuous activity, compared with inactive women.

Because most women who exercised strenuously also reported moderate activity, the investigators combined those two activity categories and again found approximately a 20 percent reduction in stroke risk that clearly was being driven by the benefits of moderate activity, said Beckham Research Institute at the City of Hope, Duarte, California. Stroke risk reductions ranged from 15 percent to 23 percent in the combined activity analysis for the 1995-1996 surveys.

Surveyed again in 2005-2006, women who reported moderate or strenuous activity in the prior three years were 12 percent - 20 percent less likely to develop a stroke, said at the meeting, sponsored by the American Heart Association.

More than five hours of activity was not more beneficial than fewer hours. Stroke reduction benefits seemed greatest with 3.5 to five hours of activity per week, which was associated with a 23 percent risk reduction in the earlier survey and 29 percent reduction in the later survey. With more than five hours, the risk reduction was 17 percent and 27 percent, respectively.

In active postmenopausal women, current hormone use was associated with a 59 percent higher risk for stroke and former house use was associated with a 16 percent increased risk compared with postmenopausal women who didn’t use hormones. However, the elevated stroke risk with hormone use fell in women who exercised, compared with those who didn’t.